JPH02225985A - Noise suppressor for cooling device - Google Patents

Abstract

PURPOSE:To enable suppression of noises, simplification of constitution and reduction of a production cost by providing a sound receiver and an opening part for radiation at the position which is acoustically symmetric to a plurality of noise sources. CONSTITUTION:A sound receiver 14 for detecting a sound produced from both noise sources 12, 13 is acoustically symmetrically arranged to both the noise sources 12, 13. On the other hand, even a radiation opening part 15 at the contrary side of the sound receiver 14 on the side face of a machine house 11 is acoustically symmetrically arranged for both the noise sources 12, 13.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a silencer used in a cooling device such as a refrigerator;
In particular, the present invention relates to a silencer for a cooling device that actively cancels out noise from a machine room housing a noise source such as a compressor.

(Conventional technology) For example, refrigerators are often installed in the living spaces of ordinary households and are operated continuously regardless of the season, so reducing noise is an issue. It has become. In this case, the most problematic source of noise in the refrigerator is noise from the machine room in which the compressor and the piping system connected thereto are housed. That is, in the machine room, the compressor itself makes relatively loud noises (compressor motor operating noise, fluid noise due to compressed gas, etc.).

The moving mechanical elements of the compression mechanism generate mechanical noise, etc.), and the piping system connected to the compressor also generates noise due to its vibration, and such mechanical room noise is caused by refrigeration I11? It accounts for most of the noise. Therefore, suppressing the noise from the machine room greatly contributes to reducing the noise of the entire refrigerator.

Therefore, conventional measures to reduce noise from the machine room include reducing the noise of the compressor itself (for example, using a rotary compressor), improving the vibration-proof support structure of the compressor, and improving the shape of the piping system. By doing this, vibration damping in the vibration propagation path can be achieved, or
By arranging sound absorbing members and sound insulating members around the compressor and the piping system, attempts are being made to increase the amount of absorption in the machine room and to increase the noise transmission loss.

(Problem to be Solved by the Invention) Generally, the machine room of a refrigerator is provided with multiple openings for heat radiation in order to release the heat generated by the compressor to the outside. Noise will leak from the area to the outside.

For this reason, the conventional noise reduction measures mentioned above naturally have their limits, and the noise level reduction effect is at most 2 dB (A
) can only be expected.

On the other hand, in recent years, with the development of electronics application technology, especially acoustic data processing circuits and acoustic control technology, the application of active noise control technology, which reduces noise using sound wave interference, has attracted attention. has been done. That is, this active control basically converts the sound from the noise source into an electrical signal using a sound receiver installed at a specific position, and
By operating a control sound generator based on a signal processed by a calculation unit from this electrical signal, the sound generator emits a signal that is in opposite phase to the original sound (sound from the noise source) at the control target point, and has the same wavelength and same wavelength. The idea is to attenuate the original sound by generating an artificial sound with a certain amplitude and causing the artificial sound to interfere with the original sound.

However, when such active noise control is used to reduce machine room noise in a refrigerator, there are the following drawbacks when there are multiple noise sources.

For example, as shown in FIG. 2, if there are two noise sources 2.3 in the machine room 1, the sound receiver 4 is placed on one side of the machine room 1, and the heat radiation opening 5 is placed on the other side. It is conceivable to provide a control sound generator 6 on the side of the heat dissipation opening 5. In this case, the sound generated from the noise source 2 reaches the sound receiver 4 and the heat radiation opening 5 through the transmission paths A and B,
On the other hand, the sound generated from the noise source 3 reaches the sound receiver 4 and the heat radiation opening 5 through the transmission paths C and D.

In general, the relationship between sound transmission paths A and C and B and D is A≠
Since C, B≠D, it is acoustically asymmetric, and the sound detected by the sound receiver 4 (the sound made by raising the sound of both sound sources 2°3)
The relationship between the amount of noise and when the sound should be silenced by the heat radiation opening 5 becomes complicated, and accurate active control is impossible. In this case, one sound receiver is provided for each noise source 2 and 3, and each noise source 2
, 3 and perform active control by setting a silencing transfer function for each of them, it becomes possible to mute the noise, but this poses a problem of complicating the configuration and increasing cost.

The present invention has been made in view of the above circumstances, and its purpose is to provide a cooling system that can perform IJ control, which cancels noise generated from multiple noise sources by interference with artificial sounds, with a simple configuration. The equipment is to provide a silencer.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention converts sounds emitted from a plurality of noise sources in a machine room into electrical signals using a sound receiver, and this? a qi 7. Play the issue! :y, By operating the control sweat generator based on the signal processed by the device, the sound radiated to the outside from the heat radiation Jll opening of the machine room is actively canceled in the vicinity of the heat radiation opening. A silencer for a cooling device according to the present invention, wherein the sound receiver and the heat dissipation opening are configured to have a VfVJ with respect to the plurality of noise sources.
It is characterized by being provided at symmetrical positions.

(Function) Since the sound receiver and the heat dissipation opening are provided at acoustically symmetrical positions with respect to multiple noise sources, the silencing transfer function for each noise source is the same, making it possible to eliminate multiple noise sources. It can be treated as a single noise source. In other words, the relationship between the sound detected by the sound receiver (sound that is a combination of sounds from multiple noise sources) and the sound that should be muffled by the heat radiation opening is the same as in the case of a single noise source. Therefore, if the electrical signal output from the sound receiver is processed by the arithmetic unit based on the noise reduction transfer function of +11- and the control sound generator is driven, the noise can be actively canceled by the heat dissipation opening. be done.

In this case, one set of receivers and arithmetic units is required for a plurality of noise sources, and the configuration is simple.

(Example) The above is the first example of applying the present invention to a refrigerator.
This will be explained with reference to the figures.

11 is a machine room provided in the refrigerator main body (not shown);
Inside it, two %11 sound sources 12.13 (for example a compressor and a cooling fan or two compressors) are arranged. Reference numeral 14 denotes a sound receiver for detecting the sound generated from both noise sources 12 and 13. are placed in symmetrical positions. On the other hand, reference numeral 15 denotes a heat radiation opening provided on the side surface of the machine room 11 opposite to the sound receiver 14, and the machine room 11 is sealed except for this heat radiation opening 15. This heat dissipation opening 15 is also arranged in an acoustically symmetrical position, in this embodiment, in a geometrically symmetrical position with respect to both noise sources 12,13. In this case, the sound generated from the noise source 12 is transmitted through transmission paths A and B.
The sound generated from the noise source 13 reaches the sound receiver 14 and the heat radiation opening 15 through the transmission paths C and D. become. In this embodiment, since the sound receiver 14 and the heat dissipation opening 15 are both arranged at symmetrical positions with respect to both noise sources 12.13, the relationship between the sound transmission paths A, C4, B, and D is as follows: −
C, B-D.

On the other hand, the electrical signal output from the sound receiver 14 is
6, the signal is processed based on a predetermined silencing transfer function, and the signal after the er calculation process drives a control sound generator 17 such as a speaker placed near the heat dissipation opening 17. The out-of-phase sound is emitted from the sound generator 5 17 toward the heat radiation opening 15 side.

According to the embodiment described above, since both the sound receiver 14 and the heat dissipation opening 15 are arranged at acoustically symmetrical positions with respect to both noise sources 12 and 13, the noise reduction for each noise source 12 and 13 is performed. The transfer functions become the same, and both noise sources 1.2.13 can be treated as a single sound source. In other words, the relationship between the sound detected by the cradle 14 (the sound obtained by superimposing the sounds of the two sound sources 12.1') and the sound to be silenced by the heat radiation opening 15 is the same as that of a single noise source. Since the situation is the same as in the case, the receiver 1
When the electric signal outputted from the heat dissipation opening 15 is processed by the arithmetic unit 16 based on a single silencing transfer function and the control sound generator 17 is driven, the heat radiation opening 15 actively cancels out the noise. be able to.

In this case, for the two noise sources 12 and 13, the pedestal 14
Only one set of arithmetic unit 16 is required, and the configuration is simple and manufacturing costs can be reduced.

In the above embodiment, the "acoustically symmetrical position" is set to the "geometrically symmetrical position," but the flow condition of the air in the machine room 11 and the temperature distribution of the air in the machine room 11 Since the state of sound propagation changes subtly due to factors such as changes in air density, etc., the ``acoustically symmetrical position'' may be determined experimentally, taking these factors into consideration. .

In addition, the present invention is not limited to the embodiments described above and shown in the drawings; for example, the silencer according to the present invention may be
In addition to refrigerators, it can be applied to outdoor units of air conditioners, refrigerated showcases, etc., and it can also be applied to devices with three or more noise sources, so it can be implemented with various modifications without departing from its gist. can do.

[Effects of the Invention] As is clear from the above description, the present invention has a sound receiver and a heat dissipation opening located at symmetrical positions with respect to a plurality of noise sources. The silencing transfer functions for the sources become the same, and multiple noise sources can be treated as noise sources.For this reason, if one set of receiver and computing unit is used for multiple noise sources, the active It is possible to muffle noise through control, simplify the configuration, and reduce manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a machine room portion showing an embodiment of the present invention, and FIG. 2 is a view corresponding to FIG. 1 for explaining the prior art. In the figure, 11 is a machine room, 12 and 13 are noise sources, 14 is a sound receiver, 15 is a heat radiation opening, 16 is a computing unit, and 7 is a control sound generator.

Claims (1)

[Claims] 1. By converting the sounds emitted from a plurality of noise sources in the machine room into electrical signals using a sound receiver, and operating the control sound generator based on a signal processed from this electrical signal by a computing unit, A sound damping device for a cooling device that actively cancels sound radiated to the outside from a heat radiation opening in a machine room in the vicinity of the heat radiation opening, the sound receiver and the heat radiation opening comprising: A silencer for a cooling device, characterized in that: is provided at a position that is acoustically symmetrical with respect to the plurality of noise sources.